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Flashcards in Retinal Transduction Lec11 Deck (99)
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1

what is the fovea? the small depression at center of macula with the ___

 highest spatial acuity

2

what enters and leaves the optic disk?

blood vessels enter and retinal axons leave the eye

3

: ant. ciliary and long post. ciliary arteries  supply blood to the

iris and ciliary body

4

Uveal tract consists of three structures: 

 choroid, the ciliary body and the iris.

5

Delivery of metabolic substrates and oxygen to the retina is accomplished by  (2) 

 the inner retinal and choroidal. 

6

what is the posteriro chamber

Region between the vitreous and the lens.

7

what produces aqueous humor?

the vascular component of the ciliary body.

8

where is the vitreous humor 

 the space between the back of the lens and the surface of the retina.

9

what pigment does the macula contain?

 a yellowish pigment (xantophyl). Supports high acuity.

10

The ocular vessels are derived from the

all from the ophthalmic artery (OA),

11

what are the two distinct vasciualr systems that supply the eye 

 a) the anterior segment (iris and ciliary body)

b) the retinal systems.

12

 Focusing Power of a lens = 

Curvature of surface + differences in Refractive Indexes

13

focal length - how strongly a lens ___

converges light.

14

Greater lens curvature = Greater converging power = __ focal length

Shorter

15

diopters - measure of 

optical power.

16

dipopeter = 

1/focal length

17

emmetropic eye - is

elaxed, unaccommodated, focused on object at “infinity”

18

what is responsible for most of the refraction in the eye

Cornea - 80%

lens does 20%

19

Refractive index of cornea = 

1.37

20

accommodation - the___ to focus on near objects

 curvature of the lens increases

21

what muscles contract to increase the curvature of the lens? which relax?

ciliary muscles contract, zonule fibers relax

22

when the curvature of the lens increases the focal length

decreases

23

Accommodative triad/near reflex:

eye accomm. + pupil constriction + eye convergence

24

eye accomm. + pupil constriction  is mediated by the 

parasymp. nerves from Edwin Westphal nucleus of pretectum

25

The ___ lens is transparent, has crystallins, with high refractive index of 1.42,

crystalline

26

• cataract - disorder of___ that destroys lens transparency,

 lens cell fibers or aggregation of crystallin

27

___ is the leading cause of blindness worldwide.

cataracts

28

risk factors for cataracts 

 aging, diabetes, sunlight, smoking

29

sx of cataracts 

hazy vision, poor night vision, glare, faded colors

30

tx of cataracts includes 

surgical replacement with an artificial lens